African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12179

Full Length Research Paper

Genetic and morphological diversity among sweet potato (Ipomoea batatas (L) Lam.) accessions from different geographical areas in Malawi

Felistus Chipungu
  • Felistus Chipungu
  • Bvumbwe Agricultural Research Station, PO Box 5748, Limbe, Malawi.
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Wisdom Changadeya
  • Wisdom Changadeya
  • DNA Laboratory, Molecular Biology and Ecology Research Unit (MBERU), Department of Biological Sciences, Chancellor College, University of Malawi, P.O. Box 280, Zomba, Malawi
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Aggrey Ambali
  • Aggrey Ambali
  • NEPAD African Biosciences Initiative, Policy Alignment and Programme Development Directorate, NEPAD Agency, c/o CSIR Building 10F, Meiring Naude Road, Brummeria, Pretoria 0001, Republic of South Africa
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John Saka
  • John Saka
  • University of Malawi, University Office, P.O. Box 278, Zomba, Malawi
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Nzola Mahungu
  • Nzola Mahungu
  • The International Institute of Tropical Agriculture (IITA), Central Africa Hub, 4163, Avenue Haut-Congo, Commune de la Gombe, Kinshasa, Democratic Republic of Congo (DRC).
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Jonathan Mkumbira
  • Jonathan Mkumbira
  • Tea Research Foundation of Central Africa, P.O. Box 51, Mulanje, Malawi.
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  •  Received: 02 May 2017
  •  Accepted: 24 May 2017
  •  Published: 31 May 2017

Abstract

An understanding of morphological and genetic diversity of sweet potato landraces is fundamental to any breeding program in a country. Fifty-nine sweet potato accessions from three eco-geographical populations of northern, south eastern and southern Malawi were examined using ten Simple Sequence Repeats (SSR) loci and seven International Board for Plant Genetic Resources (IBPGR) descriptors of sweet potato. The study generated a total of 30 alleles with a mean of 3 alleles per locus and a range of 2 to 5 alleles per locus. The primers were highly polymorphic and discriminatory with Polymorphism Information Content (PIC) mean of 0.55 and a range of 0.29 to 0.75, implying that allelic diversity and molecular relationships revealed by the study are strongly supported. Mean Nei’ gene diversity (h=0.30) and Shannon information index (I=0.43) showed moderate genetic diversity of the populations with landraces (h=0.32; I=0.47) exhibiting more genetic diversity than introductions (h=0.25; I=0.38). SSR and morphological markers differently distinguished the accessions as evidenced by poor correspondence of genetic and morphological distance matrices (Mantel’ Test, r=0.1095). However, cluster analysis indicated high variability among accessions at morphological (50% dissimilarity) and genetic (64% dissimilarity) level. Therefore, Malawian sweet potato landraces harbour considerably high morphological and genetic diversity warranting use in breeding programs.

 

Key words: Simple sequence repeats (SSR) loci, morphological diversity, sweet potato accessions, genetic diversity, descriptors, polymorphism.